In this level, you will be reintroduced to the Flood who have managed to infest parts of the station. Save for a brief Banshee excursion, you'll be doing this one entirely on foot. The level begins with a series of three unskippable battles, where you are beset on all sides by infection, combat, and carrier forms. Thereafter, you'll encounter a number of heretics fighting a rear guard action in hopes that their leader will escape. In contrast to the first part of the level, your progress from this point onward is relatively fast-paced, and includes some battles that can be outright avoided with proper use of active camouflage. Finally, it culminates with Halo 2's very first boss battle.

Its time for you to be reintroduced to the Flood who have somehow been released on this station. They generally behave pretty much the same as inHalo: Combat Evolved, though their arsenal has been expanded accordingly and their melee attack is now often a one-hit kill. The exploding Carrier Forms seem to do less damage than in the previous game, while the Infection Forms seem to do considerably more. The Combat Forms have acquired a few more tricks, like driving vehicles and using shields, but that's a problem for a later day. Although it won't affect you on this level, eventually you'll find that the Shotgun does not seem quite as effective as it used to be; in its place, though, the Energy Sword has stepped up as the ultimate Flood-killing device.

If you have followed the guide from the previous level, you will have discovered the Infinite Energy Sword glitch. Although the indicator reads 0 and the blade is invisible, it will otherwise sound, act, and wreak devastating carnage just like it did when fully charged. Note: however, that if you drop the sword, you won't be able to pick it up again.

If you restart the level, you should keep the Fuel Rod Gun, but lose the unlimited energy sword. Therefore, be especially careful with your checkpoints throughout this level and make sure to save and quit only when you are satisfied that you are in a good spot, unless it doesn't matter to you.

Now, head through the doors, ignoring the battle raging beneath you, until you drop down into a room with green stained walls with a number of dead Combat Forms on the floor. The Heretic Leader will soon pay you a visit in the form of a hologram. Once the message cuts off, a number of Infection Forms will enter the room. A new twist to battling the Flood is introduced here: Infection Forms can now reanimate dead combat forms, as long as the bodies remain intact. Fortunately, you can preempt this little surprise by destroying all five of the dead combat forms with the sword before the Infection Forms start appearing. Having eliminated the threat of the Combat Forms, there's really nothing to this first battle, just a few infection forms which your team will mop up easily, but it's best that you don't try to save the Grunts, as they are so vulnerable to the Flood since they don't have shields. They die after one Infection Form attaches to them, and plus, even if you do manage to save them the next battle will most likely kill them. After a few waves, the door will open and you can proceed onward until you reach a round platform, where you'll find the Flood and some sentinels already engaged in battle.

This next battle is fairly long. There is, however, a way around the battle on the elevator. as mentioned above, you are able to jump on the sides of the elevator shaft that are jutting out on the sides. when you do this, which takes a little of luck and skill, you can jump down the elevator shaft and circle your way down to the platform below. the reason you must circle is there are no ledges or outcroppings to jump on immediately below your current position so you must circle the shaft just like a giant circular staircase.

For those who can't do the shortcut mentioned above, here is the rundown of your battle.

Once you kill off the first group, the platform will begin its ponderous, twisting descent, stopping periodically to allow waves of about 2-4 Flood forms (and, less frequently, a few sentinels) to attack you. The encounters are fairly chaotic, and essentially amount to waiting around for the flood to appear and then hacking them to bits with your sword. However, there are a few observations that might make your life a bit easier. In general, your job will be to kill off the Flood Combat Forms as quickly as possible while you let your Elites deal with the Sentinels and Infection Forms. Ideally, you want to kill the Combat Forms as soon as they land, before they have a chance to close with your Elites and beat them up with melee attacks.

Your main priority is to keep your two Elites alive at all costs, as they provide a huge amount of assistance to you in this battle, and in the next one as well. Not only do they draw fire away from you (and with their recharging shields, they survive much better than the Marines that aid the Chief), but they will also tear apart quite easily any Sentinels that show up, which is fortunate, as you are not really equipped to counter Sentinels at this point.

Your cloak can often help you out as a defensive measure, giving you a few valuable seconds of breathing room when your shields are down to disengage and head for cover to recharge. This tactic is always useful, but perhaps more so here because, trapped as you are in a relatively small, confined space, you don't have very good avenues of retreat. Likewise, moving beneath the elevated ramp and staying near the spindle in the center can at least help to shield you from the Sentinels while your Elites blast them apart. Note that the steel canisters around the edge of the platform will release a few Infection Forms if broken, so be careful if your shields are low. It may occur to you to try switching your Fuel Rod Gun temporarily for a Carbine or Plasma Rifle so you can join in the fight against the Sentinels. It's certainly a reasonable option, as long as you keep track of it and don't let it get knocked over the edge, though. Note that if you do hand it off to one of your minions and he dies, it then becomes an enemy-dropped weapon, which will soon disappear unless you pick it up again. Grab a Plasma Pistol or Sentinel Beam; it will be useful against both the Flood and Sentinels.

Other than that watch your motion tracker, keep an eye on where your Elites are firing, and try to position yourself to intercept each wave. Make sure to destroy any intact Combat Form corpses after each battle to prevent their resurrection. Remember that all it takes to kill a Combat Form is one sword slash. The lunge, while often useful for its mobility, is overkill, and actually can be a disadvantage when used in the wrong situation (e.g., when you're faced with two or more enemies) due to its slower rate of attack. It can also cause you to lunge off of the platform resulting in you falling to your death.

Eventually, you'll wind your way down to an open door near the bottom. It's actually possible to drop down to this platform without dying near the very end of the battle, allowing you to skip the last few waves of flood. You're better off just sticking it out a little while longer and going into the next battle with your two elites to support you.

When the platform stops at the bottom, continue onward through the doorway and down the hall. Eventually, you'll find yourself on the second floor of an open, two-level room lined with breakable windows. Below you, a battle between the Heretics and the Flood already rages; the Flood will always be victorious, and it's up to you to choose at what point you want to join in. In generally, it's probably safer to wait until the battle is over before you move in (even through a few annoying Combat Forms will drop in to pester you). Unfortunately, though, you have no control over your Elites, and they may or may not jump down into the fray at their own whim. If they do this, its a good idea to follow their lead, and then try to keep them alive as long as possible.

Again, this is a fairly chaotic battle. There are some helpful observations to consider for it though. Clearly, the safest approach is to stay out of the open, along the edge of the room where you can use the columns for cover as necessary. After the first wave of Flood is eliminated, another group of Heretics will appear from the same entrance that you did, so you may want to remain underneath that side to avoid fire from above. Shortly thereafter, more waves of Flood will show up to harass you and the Heretics alike. If the Infection Forms really begin to annoy you, you might consider temporarily switching your Fuel Rod Gun for a Sentinel Beam; just make sure you don't lose track of it, or forget to pick it up when the battle is over. The Plasma Turrets at the other end of the room can we quite useful for picking off the Flood, but can leave you vulnerable to the Heretics.

Shortly after you kill the last of the Combat Forms, the airlock door at the end of the room will open and a group of Heretics (two Elites and three Grunts) will show up. Staying in the vicinity of the door so you can attack while they're still bunched up in the entrance can make them a bit easier to handle, as the next video shows.

If you dropped your Fuel Rod Gun at some point during the previous battle, don't forget to retrieve it before moving too far into the airlock, or else the doors will lock behind you and you'll be out of luck.

Once you're outside, a Phantom will drop off reinforcements and blast the Flood gathered on the bridge. The next area presents you with a choice of two symmetric routes where you'll encounter a few scattered elites and grunts, as well as larger group of 2 Elites & (sometimes) 3 Grunts that appear from the door at the top. As the next video shows, split up as they are, your enemies shouldn't provide much of a hindrance. The limited line of sight on the winding pathway and the abundance of cover (not to mention your cloaking device) should help you get close enough to make short work of them with the sword.

Inside, you'll find a vast room dominated by the presence of a central ramp winding upward to an elevator platform. The Heretic Leader flees to safety behind an impenetrable energy barrier, any efforts to kill him before he reaches safety will be unsuccessful. Fortunately, during the cutscene the Arbiter comes up with a plan to flush him out.

You may wish to try to avoid the first group of Flood on the ramp because they can often serve as an effective distraction for the sentinels. In a similar manner, your safest bet in the area with the cables is to remain as unobtrusive as possible, avoiding combat with the Flood or Sentinels unless absolutely necessary while you make your way quickly and quietly around the outside.

NOTE: When you're waiting for it to say 'Loading....Done',then you're able to use the elevator,right?
Spartan 148 Sera's advice is,when it says 'Loading....Done',do not,I repeat do not press the 'A' button.

By the time you head back down in the elevator the Heretic Leader, and the energy barrier has disappeared. Take the express route back to the ground (i.e. jump down instead of using the ramp) and follow him through the now-unsealed doorway, where you'll have to deal with two Elites and two Grunts, as the next video shows.

Keep an eye out for the Combat Forms that runs into the room a few moments after you take out the Covenant. When you're ready, hit the button on the side of the elevator to raise it, and then the central button to send it back down again.

Or, alternatively, you could cloak just outside of the doorway and run through the room, ignoring the Heretic forces before dropping down the elevator shaft to the next level.

For all its size, the next area is rather sparsely populated, with only a couple of Sentinels and Grunts followed by two sword-wielding Elites to oppose you. As the next video shows, you may want to drop your Fuel Rod Gun temporarily to pick off the grunts with one of the Carbines provided along the way.

Indeed, you're simply retracing the same path that you walked in the previous level back to the hangar with the docked Heretic Seraph. Opposition here is pretty thin, and you can cruise right through the majority of the route with little trouble. The only seriously tricky spot is in the final room before you reach the Heretic Leader, as you have quite a bit of open ground to cover and several enemies in your way. Depending upon their initial position, it's not always easy to make it through the door before your cloak runs out. You should receive a checkpoint close by, though, so just reload and try again if you run into serious trouble. It may be tempting to expend a few Fuel Rod rounds here to clear the path, but its best to save them all for the finale, just in case. However, you may want to be careful of where your shots go, because if they hit the gas canister, the canister(s) will explode.

As the cutscene with the Heretic Leader ends, you'll receive a checkpoint, its very strongly recommend that you save and quit here. As with some of the earlier battles, you'll receive additional checkpoints throughout the upcoming fight, and some of them may turn out to be inconvenient (though, with the Fuel Rod Gun, this is less of a problem than it normally might be). After all the work it took to get to this point, you don't want to wind up stuck at the end.

Regenerating supply of disposable henchmen. Still largely unwilling to fight his own battles, the Heretic Leader will surround himself with holographic duplicates in an admittedly effective attempt to confuse us.

The battle is divided into four rounds, the first of which begins as soon as the cutscene ends. During the first three rounds, the Heretic Leader shows up with two holographic duplicates of himself. Your mission is to blast him with one Fuel Rod in each round, which is all it takes to send him running for cover. The holograms are indistinguishable from the real thing until after you've hit them. At that point, you'll either hear your target vanish in a poof (if it was a hologram) or yell in pain (if it was the leader). The final round can be a bit tricky, as he can potentially deploy more than two holograms, and you'll have to hit him twice in succession to finish him off. Other than that, though, it's the same story as before. Note that his holograms will vanish as soon as he runs off.

Now this battle could actually be quite tricky if we hadn't come loaded for bear, as the Heretic Leader and his holograms are somewhat difficult to target and can do a tremendous amount of damage. Fortunately, the patience you showed in carrying that Fuel Rod Gun around for the last 1.5 levels is about to pay off big time. The Heretic Leader begins each round (after the first) by appearing randomly from one of the four vents near the ceiling. Unwisely and foolishly, he stands there in plain view taunting the Arbiter before flying out to attack. Although he's invulnerable between rounds while he is talking, he is fair game when he stops talking.

So, as the next video shows, your job in the time allotted to you between each round is simply to locate the correct vent, aim in, and then spam the hell out of it with the Fuel Rod Gun as soon as his little speech is over. Given the travel time of your shots, you'll want to begin firing a bit early so the rounds start to impact just as he finishes talking.

The purists can now rejoice, as the next level will find us back in the familiar armor of the Chief.

There is an alternate way, and this one saves you from lugging the Fuel Rod Cannon around for the whole level. When the cutscene finishes and the battle begins, stick one of the holograms with a plasma grenade. Run to the alcove on your left, and pick up the Plasma Rifle. When the boss and the remaining drone start firing at you, cloak and run around to your left. The two bosses will (hopefully) still be firing into your previous hiding place. Stick them both with Plasma Grenades.

If you still can't do that, then here's what you do:
(note that this only works about 50% of the time)
Dual-wield Needlers. After the cutscene, run, jump, or cloak past the first two ones. Then dump all the ammo you can into him. It usually kills him in less than a minute.

The easiest way to kill the Heretic Leader (in lower levels) is to just run past the first two holograms and use your Energy Sword to kill him. You can also turn on your camo and stab him.